Sheet handling apparatus and method for multicolor perfector press



United States Patent [72] Inventors Harry E. Mowry;

Guy F. Werner, Pittsburgh, Pennsylvania [211 App]. No. 676,188 [22]Filed Oct. 18, 1967 [45] Patented Nov. 3, 1970 [73] Assignee MillerPrinting Machinery Co.

Pittsburgh, Pennsylvania a corporation of Pennsylvania [54] SHEETHANDLING APPARATUS AND METHOD FOR MULTI-COLOR PERFECTOR PRESS 12 Claims,10 Drawing Figs.

Primary Examiner-Robert E. Pulfrey Assistant Examiner.l. Reed FisherAttorney-Stanley .l. Price,.lr.

ABSTRACT: A sheet fed offset printing press having a perfecting cylinderwith suction means disposed longitudinally along the periphery of thecylinder and pairs of tumbler grippers positioned adjacent to thesuction means. The suction means is arranged to engage the trailing edgeof a sheet on an adjacent impression cylinder and transfer the trailingedge of the sheet to the adjacent pairs of tumbler grippers. Thetrailing edge of the sheet .is reversed by the tumbler grippers andbecomes the leading edge of the sheet. The sheet with the formertrailing edge as the leading edge is then transferred to an adjacentimpression cylinder. The suction means is mounted for limited rotationalong the periphery of the perfecting cylinder to tension the sheet onthe adjacent impression cylinder before the sheet is released from theimpression cylinder to remove wrinkles present in the sheet. The suctionmeans may also be arranged for limited sliding movement relative to thesheet so that all of the sheets are engaged by the suction means at thesame location adjacent the trailing edge of the sheet. The trailing edgeof the sheet is engaged by the suction means when the suction means istangent to the adjacent impression cylinder and transfers the sheet tothe first pair of grippers at a location where the tumbler grippers arebeyond the tangent point with the first impression cylinder.

With this arrangement, the pair of tumbler grippers can extend beyondthe periphery of the perfecting cylinder during transfer of the sheetthereto from the suction means.

Patented Nov. 3, 1970 3,53 7,391

Sheet 1 of 2 mum r095 HARRY 7 MOWR) y our F WERNER ATTORNEYS PatentedNov. 3, 1970 3,537,391

Sheet 2 of 2 l/VVE/VTOAS HARRY .E. MOW/W Z6 cur F? WERNER BK ATTORNEYSSHEET HANDLING APIARATUS AND METHOD FOR MULTI-COLOR PERFECTOR PRESSBACKGROUND OF THE INVENTION l. Field of the Invention This inventionrelates generally to sheet fed offset printing presses having aperfecting cylinder. More particularly the invention relates to a sheetfed offset printing press wherein the perfecting cylinder has suctionmeans to engage the trailing edge of the sheet and tumbler grippers forengaging the trailing edge of the sheet from the suction means andchanging the trailing edge to the leading edge ofthe sheet.

2. Description ofthe Prior Art A sheet fcd rotary printing press adaptedto be employed either as a multicolor press or as a perfecting press isknown. A comprehensive disclosure ofthis press is found in U.S. Pat. No.2,757,(il(l granted to Gegcnheimer et al. In this patent a thirdtransfer cylinder or perfecting cylinder receives the sheet from asecond impression cylinder after the first printing operation. The thirdtransfer cylinder is designed to receive and transfer the sheet in sucha fashion that the second printing will be applied either to the sameside of the sheet as the first printing, [.e. multicolor printing oralternatively to reverse the sheet so that the opposite side ispresented to the second printing unit, i.e. perfecting printing.

The third transfer cylinder or perfecting cylinder is provided with aseries of two-color grippers and a closely adjacent series of perfectinggrippers. In the normal direction of rotation of the cylinder, thetwo-color grippers are disposed behind the perfecting grippers. When thecylinder is employed in two-color printing, the two-color grippers graspthe leading edge of the sheet from the second transfer cylinder. Thethird transfer cylinder then, through the twocolor grippers, transfersthe leading edge of the sheet to the second impression cylinder withoutreversal.

When the third transfer cylinder is arranged to operate as a perfectingcylinder, the perfecting grippers, while abutting an outer stop member,engage the trailing edge of the sheet on the second transfer cylinder.The perfecting grippers rotate or tumble inwardly about their own axesinto abutting relation with an inner stop member and the two-colorgrippers also tumble inwardly about their own axes into abuttingrelation with a similar inner stop member. The trailing edge of thesheet is transferred from the inwardly tumbled perfecting grippers tothe mating two-color grippers to thus invert the sheet with the trailingedge from the second transfer cylinder becoming the leading edge. Theoriginal trailing edge is thus transferred from the two-color grippersto the second impression cylinder as the leading edge of the sheet sothat the sheet is printed on the opposite side. With the mechanicalgripper devices of the Gegenheimer patent abutting fixed mechanicalstops in both the inner and outer position, the pickup, transfer anddelivery of each sheet is exactly the same and desired registry ismaintained.

The Gegenheimer et al. patent also discloses the use of suction deviceson the periphery of the second transfer cylinder. The suction devicesare peripherally spaced from the grippers on the transfer cylinderapproximately the length of the sheet being handled. The suction devicesare disposed behind the grippers with respect to the direction ofrotation of the second transfer cylinder so that the trailing edge ofthe sheet is in overlying relation with the suction devices on thesecond transfer cylinder. After the grippers on the second transfercylinder secure the leading edge of the sheet, the suction devices areactuated to cause the suction heads to engage the trailing edge of thesheet and thereby secure it to the cylinder periphery. When the secondtransfer cylinder has rotated to the point where the trailing edge ofthe sheet is on a line intersecting the centers of the second transfercylinder and the third transfer cylinder, the suction is released andair is blown outwardly through the suction devices to facilitateseparation of the sheet from the second transfer cylinder, andengagement by the perfecting grippers on the third transfer cylinder.

i The suction devices may be adjusted peripherally on the secondtransfer cylinder by moving them angularly about the centrallongitudinal axis of the second transfer cylinder. The adjustment of thesuction device establishes a peripheral spacing with respect to thegrippers on the second transfer cylinder that corresponds to the lengthofthe sheet to be handled.

With the pairs of tumbling grippers such as those disclosed inGegenheimer et al. US. Pat. No. 2,757,610, the grippers extend beyondthe periphery of the cylinder on which they are mounted when theperfecting grippers engage the trailing edge of the sheet. The sheethandling mechanism disclosed in the (legenlteimer ct al. patent includesa second transfer cylinder with peripheral recessed portions. Theextending grippers on the perfecting cylinder fit into these recessedportions to en gage the trailing edge ofthe sheet as above discussed.

To provide a perfecting typc press with impression cylinders on oppositesides of a single transfer cylinder that may also serve as a perfectingcylinder, it has been suggested that the perfecting cylinder includesuction devices mounted on the periphery of the perfecting cylinder thattumble inwardly relative to the periphery of the perfecting cylinder.The rotatably mounted suction devices serve in effect, as perfectinggrippers. The perfecting cylinder also includes rotatable grippersmounted behind (with respect to the direction of rotation of thecylinder) the suction devices. With this arrangement. it has beensuggested in perfecting that the suction devices en gage the trailingedge of the sheet on an adjacent cylinder. The suction devices thentumble inwardly and transfer the trailing edge of the sheet to theinwardly tumbled grippers. The grippers, which are similar to thetwo-color grippers in Gegenheimer et al., then rotate outwardly totransform the trailing edge of the sheet into the leading edge of thesheet and transfer the sheet in its reversed position to an adjacentimpression cylinder.

One ofthe major weaknesses with the above suggested solution is registryof the sheet for subsequent printing. The transfer of the edges of thesheet during perfecting requires great precision which is not possiblewith the above discussed rotatable suction devices on the perfectingcylinder. It has been found that the trailing edge of the sheet must begripped firmly by the perfecting grippers during transfer to thetwocolor grippers in order to maintain registry. There are substantiallimitations in the use of suction devices for transferring sheets fromone cylinder to another. These limitations are magnified when thesuction devices are rotated or tumbled inwardly about their own axesbefore the sheet is transferred to the grippers.

The suction devices, for example, engage the trailing edge of the sheetwhile the leading edge of the sheet is engaged by grippers on theadjacent cylinder and tensions the sheet by tumbling inwardly before theleading edge of the sheet is released by the grippers on the adjacentcylinder. The suction devices continue to tumble inwardly to the innerposition where the suction devices transfer the sheet to the grippermechanisms. The movement of the suction devices is thus continuous fromthe time they engage the sheet until the time they are in position totransfer the sheet to the gripper devices. During this time interval,registry depends solely on the suction devices. Any flutter, vibrationor motion of the sheet during this time interval will affect register.

Another major problem with the above suggested perfecting arrangement isthe wrinkling of the sheet while on the first impression cylinder. Inthe suggested press, the sheet is engaged only by its leading edge onthe impression cylinder and the trailing edge of the sheet is notpositively engaged to the first impression cylinder. It is well knownthat the sheet tends to adhere to the blanket cylinder because oftheadhesive properties of the ink. This factor alone would cause thetrailing edge of the sheet to pull away from the first impressioncylinder and cause the sheet to wrinkle. Another factor, Le. thecentrifugal force of the rapidly rotating impression cylinder, wouldcause the trailing edge of the sheet to become disengaged so thatwrinkling of the sheet would occur. The herein described inventioneliminates the above discussed problems and now provides a perfectingpress arrangement wherein the sheet is transferred directly from animpression cylinder to the perfecting cylinder, the edges reversed andthen transferred directly to a second impression cylinder while registryis maintained and the sheet remains free of wrinkles.

SUMMARY OF THE INVENTION The hereinafter described invention includes aperfecting cylinder that has suction devices adapted to engage thetrailing edge of the sheet at the tangent point with the adjacent firstimpression cylinder. The suction devices on the perfecting cylinderengage the trailing edge of the sheet while the leading edge of thesheet remains engaged by the grippers on the first impression cylinder.The suction devices then move along the periphery of the perfectingcylinder into abutting relation with a mechanical stopmember and tensionthe sheet to remove any wrinkles present in the sheet. The suctiondevices secure the trailing edge of the sheet to the perfecting cylinderand permit the perfecting cylinder to rotate to a position where theperfecting grippers are free to tumble outwardly beyond the periphery ofthe perfecting cylinder to a predetermined position controlled by a stopmember and engage the trailing edge of the sheet. After the trailingedge of the sheet is engaged by the perfecting grippers, the suctiondevices release the trailing edge of the sheet. The perfecting cylindercontinues to rotate and the perfecting grippers and two-color gripperstumble inwardly toward each other to a preselected position controlledby stop members while the trailing edge of the sheet is securely engagedby the perfecting grippers. The trailing edge of the sheet is thentransferred to the two-color grippers and the grippers tumble outwardlyto a preselected position where the trailing edge of the sheet, now theleading edge of the sheet is transferred to the grippers on the secondimpression cylinder. With this arrangement, a tension is first exertedon the sheet by the suction means to remove wrinkles therefrom and thesuction means moves to a preselected position on the cylinder and abutsa mechanical stop means. In this position, the perfecting grippersabutting an outer stop member engage the sheet edge portion for transferto the two-color grippers. The perfecting grippers firmly hold the sheetwhile the trailing edge of the sheet is transferred from one set ofgrippers to others. Because of the arrangement of the stop members forthe suction means and the gripper devices, sheet flutter, vibration andthe like does not result in loss of registry as would occur in theabsence of positive stop members for the suction means and the grippers.

Accordingly, it is an object of this invention to provide a sheet fedperfecting press with a pair of impression cylinders adjacent to aperfecting cylinder and where a sheet is maintained in registry when itis transferred from the first impression cylinder to the secondimpression cylinder by the perfecting cylinder.

Another object of this invention is to provide a perfecting cylinder foruse with adjacent impression cylinders that includes a means to removewrinkles from the sheet on the first impression cylinder while registryis maintained.

It is a further object of this invention to provide a perfectingcylinder arranged to receive a sheet from an adjacent impressioncylinder, reverse the edges of the sheet by suction devices and pairs oftumbler grippers and transfer the sheet in reversed position to a secondimpression cylinder while maintaining accurate registry during thetransfer and sheet reversal.

It is an additional object of this invention to provide a sheet fedperfecting press with impression cylinders adjacent to the perfectingcylinder that is adapted to effectively handle sheets of various sizes.

These and other objects and advantages of this invention will be morecompletely disclosed and described in the following specification, theaccompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a schematic representation of the perfecting cylinder with thesuction devices, perfecting grippers and twocolor grippers. The drivemeans for the cylinder and the actuating means for the suction devicesand grippers are illustrated diagrammatically.

FIG. 2 is a schematic illustration of a perfecting press with theperfecting cylinder positioned between the pair of impression cylinders.In FIG. 2, the suction device on the perfecting cylinder is illustratedat the tangent point between the first impression cylinder and theperfecting cylinder. The suction device in FIG. 2 has engaged thetrailing edge ofa sheet.

FIG. 3 is a schematic illustration similar to FIG. 2 illustrating theperfecting cylinder rotated through approximately with the trailing edgeof the sheet being transferred from the perfecting grippers to thetwo-color grippers.

FIG. 4 is a schematic illustration similar to FIGS. 2 and 3 illustratingthe trailing edge of one sheet being transferred from the two-colorgrippers to the grippers on the second impression cylinder as theleading edge of the sheet and the trailing edge of another sheet engagedby the perfecting grippers as the perfecting grippers and two-colorgrippers tumble inwardly to each other for subsequent transfer of thetrailing edge of the sheet from the perfecting gripper to the two-colorgrippers.

FIG. 5 is a fragmentary schematic view of a portion of the perfectingcylinder and first impression cylinder illustrating the perfectinggrippers and the two-color grippers tumbled inwardly below the peripheryof the perfecting cylinder and the suction device located on theperiphery of the perfecting cylinder engaged to the trailing edge of thesheet on the impression cylinder.

FIG. 6 is a view similar to FIG. 5 illustrating the perfecting cylinderrotated to an extent where the perfecting grippers are free to tumbleoutwardly beyond the periphery of the perfecting cylinder and engage thetrailing edge of the sheet secured by the suction devices.

FIG. 7 is a view similar to FIGS. 5 and 6 illustrating the trailing edgeof the sheet engaged by the perfecting grippers.

FIGS. 8, 9 and I0 are similar to FIGS. 2, 3 and 4 and illustrate theperfecting cylinder transferring sheets that are less than full size.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings andparticularly to FIGS. 2, 3 and 4, the perfecting press includes aperfecting cylinder generally designated by the numeral I0 with a firstimpression cylinder 12 positioned adjacent thereto and a secondimpression cylinder 14 positioned on the opposite side of the perfectingcylinder 10. A feed board 16 is positioned adjacent to a pick upcylinder I0 that feeds the sheets to the first impression cylinder 12. Aconventional printing couple consisting of a plate cylinder and ablanket cylinder with suitable inkers and dampening units are associatedwith the first impression cylinder 12 and have been omitted from thedrawings to more clearly illustrate the invention. A similar printingcouple is associated with the second impression cylinder I4 and has notbeen shown for the same reason. It should be understood, however, thatany conventional well known printing couple such as that illustrated inFIGS. I and 2 of Gegenheimer et al. could be used with the illustratedimpression cylinders 12 and 14.

The impression cylinder 12 has a cylindrical surface 20 with a firstlongitudinal opening 22 and a diametrically opposed second longitudinalopening 24. The impression cylinder I2 may be of conventional well knownconstruction and is suitably supported for rotation on shaft 26. A firstset of grippers 27, only one of which is illustrated in FIGS. 2-10, issecured to a shaft within the cylinder 12 and have gripper fingers 28arranged to engage the leading edge of the sheet and maintain theleading edge of the sheet in registry on the impression cylinder 12while the upper surface of the sheet is printed. The first impressioncylinder 12 has a second set of grippers 30 mounted on a shaft inrecessed portion 24 with gripper fingers 32 arranged to engage the frontedge of a second sheet and maintain the front edge of the sheet inregistry while the sheet is being printed. The grippers 27 and 30 are ofconventional construction and suitable sets of grippers and actuatingmeans therefor are illustrated in the Gegenheimer et al. U.S. Pat. No.2,757,610, FIGS. 8 and 9.

The second impression cylinder 14 is similar to the first impressioncylinder 12 and includes a cylindrical surface with a.

first recessed portion or opening 36 and a diametrically opposed otherrecessed opening 38. Grippers 40 and 42 are rotatably secured within theimpression cylinder 14 and have gripper fingers 44 and 46 that abut theperipheral surface of the cylinder 14 and are operable to engage theleading edge of a sheet to the periphery of the second impressioncylinder 14. The second impression cylinder 14 is suitably mounted on ashaft 48 for rotation in timed relation with both the first impressioncylinder l2'and the perfecting cylinder 10.

In FIGS. 2-4 and 8-l0, only one set of diametrically opposed grippersare illustrated on each impression cylinder. It should be understood,however, that a plurality of grippers extend longitudinally along theperiphery of the cylinder surfaces 20 and 24 and the respective gripperson each cylinder are arranged to simultaneously engage the leading edgeof the sheet and firmly secure the leading edge of the sheet to thesurface of the impression cylinder while the sheet is being printed andeither transferred to the perfecting cylinder or transferred to asuitable sheet delivery mechanism.

The perfecting cylinder is suitably mounted on a shaft 50 for timedrotation with the impression cylinders 12 and 14. The perfectingcylinder 10 is illustrated as having a cylindrical surface 52 with afirst recessed portion 54 and a diametrically opposed recessed portion56. It should be understood, however, that the perfecting cylinder 10could be fabricated from a plurality of disclike members as is disclosedin Gegenheimer et al. U.S. Pat. No. 2,757,610. Positioned within therecess 54 are a plurality of suction devices 58 spaced longitudinallyalong the cylinder periphery 52. In FIG. 1, the suction devices 58extend into slots 60 that extend radially from the recessed portion 54.It should be noted, however, that the slots 60 provide for movement ofthe suction devices along the periphery 52 of perfecting cylinder 10.Similar suction devices 62 extend outwardly from the cylinder 10 andterminate along the peripheral surface 52. The suction devices 58 and 62are similar in construction and only the suction devices 58 will bedescribed in detail since the suction devices 62 operate insubstantially the same manner. The suction devices 58 have an armportion 64 nonrotatably secured'to a shaft 66 extending longitudinallywithin the perfecting cylinder 10. The arm portions 64 terminate in ahead portion 68 that has a foraminous or perforated outer end portionthat terminates at the periphery of the perfecting cylinder cylindricalsurface 52. The suction devices are arranged to move along the peripheryof the perfecting cylinder 10 to a limited extend by rotation of shaft66. The arm portion 64 of suction devices 58 are arranged upon rotationof shaft 66 in a counterclockwise direction, as illustrated in FIGS. 5-7to abut a stop member 67 to thereby limit the rotational movement andposition the sheet edge portion for engagement'by the'perfecting gripperassembly as later described.

An arrangement whereby the suction heads are permitted to move along theperiphery of the suction heads and the manner for controlling themovement of the suction heads is illustrated and described in copendingapplication Ser. No. 602,857 entitled Sheet Tensioning and TransferMechanism For Presses". The arrangement disclosed in the aboveapplication could, with equal facility, by used on perfecting cylinder10 to move the suction devices 58 and 62'for the purpose laterdescribed.

The tumbler gripper assemblies are generally designated by the numeral70 in FIG. 1 and include a perfecting gripper assembly generallydesignated by the numeral 72 and a two,-

color gripper assembly generally designated by the numeral 74. Theperfecting gripper assembly 72 and two-color gripper assembly 74 arearranged to tumble inwardly toward each other and abut stop members 73and 77 and in this position remain within the periphery of theperfecting cylinder 10. The

perfecting gripper assembly 72 and two-color gripper assembly 74 arealso arranged to tumble outwardly away from each other and beyond theperiphery of the perfecting cylinder 10 and abut stop members 75 and 79so that the perfecting grippers can engage the trailing edge of thesheet secured by the suction devices 58 on the perfecting cylinder 10and the two-color grippers can transfer the sheet to the secondimpression cylinder. The perfecting gripper assembly 72 and two-colorassembly 74 may be similar in construction to the perfecting gripperassembly and two-color gripper assembly illustrated in Gegenheimer etal. U.S. Pat. No. 2,757,610. Also, similar apparatus to that illustratedin the Gegenheimer et al. patent for tumbling the gripper assembliesinwardly toward each other and outwardly away from each othermay beemployed to tumble the perfecting gripper assembly 72 and two-colorgripper assembly 74 in the perfecting cylinder disclosed in the instantapplication. Other suitable means to tumble or rotate the perfectinggripper assembly 72 and two-color gripper assembly 74 may also be usedas long as the grippers perform the purposes hereinafter discussed.

The perfecting cylinder 10 has a second pair of tumbler gripperassemblies generally designated by the numeral 76 within the recess 56and diametrically opposed to the tumbler gripper assemblies 70. Thetumbler gripper assemblies 76 include a perfecting gripper assemblygenerally designated 78 and two-color gripper assembly 80. Theperfecting gripper as-- sembly 78 and two-color gripper assembly 80 aresimilar to the perfecting gripper assembly 72 and two-color gripperassembly 74 and will not be described in detail. The same type ofmechanism as is illustrated in Gegenheimer et al. may be used to tumblethe respective perfecting and two-color gripper assemblies 78 and 80 ina manner similar to the perfecting and two-color gripper assemblies 72and 74 as hereinafter described.

The tumbler gripper assemblies 70 and 76 are diagrammaticallyillustrated in the drawings. FIGS. 5, 6 and 7 illustrate the essentialelements of the tumbler gripper assembly 70. A perfecting grippertumbler shaft 82 extends longitudinally within the perfecting cylinder10 and is journaled for rotation therein. Nonrotatably connected toshaft 82 is an arm 84 that rotatably supports a gripper finger shaft 86.The shaft 82 has a hub portion nonrotatably secured thereto withradially extending flange portions 81 and 83. The flange portion 81(FIG. 5) is operable to abut stop member 73 and limit inward movement ofthe gripper assembly 72. Similarly, the flange portion 83 (FIGS. 6 and7)-is operable to abut stop member 75 and limit outward movement of thegripper assembly 72. Thus, rotation of shaft 82 in a clockwisedirection, as viewed in FIGS. 5, 6 and 7, causes the arm 84 to rotatetherewith and move the gripper finger shaft toward the perfectingcylinder periphery to a predetermined location controlled by flange 83.Similarly, rotation of shaft 8 2 in a counterclockwise direction causesthe arm 84 to rotate therewith and move the gripper finger shaftinwardly away from the cylinder periphery to a predetermined locationcontrolled by flange 81. Extending radially from the arm 84 is a gripperpad bracket 88 that has a gripper surface 90 thereon.

Secured to the shaft 86 and rotatable therewith are gripper fingers 92with a toe portion 94 that is arranged upon clockwise rotation of shaft82 to engage the gripper pad. surface 90 and secure a sheettherebetween. Suitable actuating I means are provided to rotate shaft 82to tumble both the gripper pad bracket 88 and gripper fingers 92inwardly toward the center of the perfecting cylinder 10 so that stopmember 73 is in abutting relation with flange 81 or outwardly toward theperiphery of the perfecting cylinder 10 so that stop member 75 is inabutting relation with flange 83. Other actuating means are provided torotate the gripper finger shaft 86 and move the gripper finger toeportion 94 into or out of engagement with the gripper surface 90.

The two-color gripper assembly 74 is similar in construction and has atwo-color tumbler shaft 96 extending longitudinally therethrough inspace relation to the perfecting gripper tum bler shaft 82. Nonrotatablysecured to shaft 96 is an arm member 98 that extends radially therefrom.The shaft 96 has a hub portion nonrotatably secured thereto withradially extending flange portions 95 and 97 (FIGS. 6 and 7). The flangeportion 95 is operable to abut stop member 77 and limit inward movementof the gripper assembly 74. Flange portion 97 is operable to abut stopmember 79 and limit outward movement of the gripper assembly 74.

A gripper finger shaft 100 is rotatably secured within the arm member 98and has gripper fingers 102 nonrotatably secured theretov A gripper padbracket 104 extends radially from the arm 98 and has a gripper surface106 thereon and the gripper finger 102 has a toe portion 108 that isarranged to abut surface 106 and engage the edge of a paper sheettherebetween. Thus, by rotation of tumbler shaft 96 the twocolor gripperassembly 74 is moved inwardly toward the center of the perfectingcylinder to a location where flange 95 abuts stop member 77. Suitableseparate means may be provided to rotate two-color tumbler shaft 96 tomove the gripper assembly. The gripper finger shaft 102 is rotatablerelative to the two-color tumbler shaft 96 to move the gripper fingertoe portion 108 into and out of engagement with the gripper surface 106.Again, suitable means are provided to separately rotate gripper fingershaft 100 to perform the functions hereinafter described.

In FIG. 1, the perfecting cylinder 10 has indicated diagrammatically andconnected thereto by dotted lines, suitable means to rotate theperfecting cylinder 10, to actuate the suction devices 58, to actuatethe suction device shaft, to actuate the perfecting gripper tumblershaft. to actuate the two-color tumbler shaft, to actuate the perfectinggripper finger shaft and to actuate the two-color gripper finger shaft.It should be understood, the various actuators may be cam means or thelike wherein the relative position of the shafts within the perfectingcylinder is determined by the relative position of the perfectingcylinder to the adjacent impression cylinder.

OPERATION Referring firstto FIGS. 2, 3 and 4 there is illustrated afirst sheet 51 that has its leading edge engaged by the grippers 32 onthe impression cylinder 12. The sheet S1 has passed through the printingcouple and has been printed on its outer surface. Note in FIG. 2 wherethe sheet S1 has a wrinkle W1 .formed therein. In FIG. 2, the trailingedge of the sheet is being engaged by the suction device 58 at thetangent point between the first impression cylinder 12 and theperfecting cylinder 10. The manner in which the wrinkle W1 is removedfrom sheet 51 is illustrated in FIG. 5. The suction head 68 is normallyin the position shown in dotted lines in FIG. 5. As the trailing edge ofthe sheet S1 is engaged by the suction device 58, the suction deviceshaft 66 rotates in a counterclockwise direction to exert a tension onthe sheet 81 on the impression cylinder periphery 20. The front edge ofsheet S1 is engaged by the grippers 32 and the movement of suctiondevice 58, as illustrated in FIG. 5, exerts a tension on the sheet 81sufficient to remove the wrinkle W1 and the suction device 58 movesagainst the stop 67 (FIG. 5) where the sheet edge portion remains infixed position on the perfecting cylinder 10. After the wrinkle W1 isremoved, the gripper device 32 on impression cylinder 12 releases theleading edge of the sheet S1 and the sheet is engaged by the suctiondevice 58 to transfer the sheet by the trailing edge from the impressioncylinder 12 to the perfecting cylinder 10. It should be noted that thesuction head 68 is coextensive with the periphery of the perfectingcylinder so that there is no interference between the impressioncylinder 12 and perfecting cylinder 10 as the suction device 58 rotatespast the tangent point between the cylinders l2 and 10 and when thesuction device 58 rotates to a predetermined position on the perfectingcylinder 10 controlled by the stop member 67. The suction device 58remains fixed and a tension is exerted on the sheet before it istransferred from the impression cylinder 12 to the perfecting cylinder10.

As is illustrated in FIG. 5, when the suction device 58 is at thetangent point between cylinders 12 and 10, the perfecting gripperassembly 72 and two-color gripper assembly 74 are tumbled inwardlytoward each other and against the respective stops 73 and 77 so thatthey are within the periphery of the perfecting cylinder 10. Theperfecting gripper assembly 72 and two-color gripper assembly 74 remainwithin the periphery of perfecting cylinder 10 as they pass the tangentpoint between the impression cylinder 12 and the perfecting cylinder 10.The trailing edge of the sheet, however, has been engaged by the suctiondevice 58, tensioned and transferred from the impression cylinder 12 tothe perfecting cylinder 10 by the suction device 58.

After the perfecting cylinder 10 has rotated to an extent that theperfecting cylinder gripper assembly 72 and two-color gripper assembly74 are beyond the tangent point between impression cylinder 12 andperfecting cylinder 10, the perfecting gripper tumbler shaft 82 isrotated in a clockwise direction as illustrated in FIG. 6 to tumble theperfecting gripper assembly 72 outwardly against the stop 75 so that thetrailing edge of the sheet S1 is in overlying relation with the gripperpad while the sheet is still engaged by the suction device 58.

After the perfecting cylinder rotates further, the gripper finger shaft86 rotates to engage the sheet edge portion between the gripper padsurface 90 and the gripper finger toe portion 94, FIG. 7. After thetrailing edge of the sheet 51 is engaged by the perfecting gripperassembly 72, the suction device 58 is deenergized to release the sheetand the trailing edge of the sheet is engaged to the perfecting cylinder10 by the perfecting grippers 72. Upon further rotation of theperfecting cylinder 10, the perfecting gripper assembly 72 engaging thetrailing edge of the sheet S1 is tumbled inwardly by thecounterclockwise rotation of perfecting gripper tumbler shaft 82 againstthe stop 73 as is illustrated in FIG. 3. The two-color gripper pad 106is in overlying relation with the perfecting gripper pad 90 and thetwo-color gripper fingers 102 are moved into overlying relation with thegripper pad 106 and engage the trailing edge of the sheet. Theperfecting gripper fingers 92 move away from the gripper pads 90 torelease the trailing edge of the sheet. The trailing edge of the sheetS1 now engaged by the two-color gripper assembly 74 becomes the leadingedge of the sheet.

The two-color gripper tumbler shaft 96 rotates in a counterclockwisedirection to move the leading edge of the sheet (previously the trailingedge of the sheet) to the periphery of the perfecting cylinder 10. Atthe tangent point between the second impression cylinder 14 and theperfecting cylinder 10, the reversed sheet is engaged by the grippers 46on the second impression cylinder 14 and transferred thereto from theperfecting cylinder 10.

Thus, with the suction devices, the tumbler grippers on the perfectingcylinder 10 and the associated stop members, it is now possible toengage the trailing edge of the sheet from an adjacent impressioncylinder by suction devices and to reverse the sheet while transferringit to a second adjacent impression cylinder and maintain accurateregistry. The versatility of the above previously described apparatus isillustrated in FIGS. 8, 9 and 10 where the sheets of less than full sizeare handled by the perfecting cylinder with the same accuracy as a fullsized sheet. With sheets of less than full size, the problem ofinterference between the first impression cylinder and adjacentperfecting cylinder 10 is exemplified. It is essential because theimpression cylinder has a continuous cylindrical surface beneath thetrailing edge of the sheet that the transfer means, [.e. the suctiondevices and the tumbler gripper assemblies, not extend beyond theperiphery'of the perfecting cylinder at the tangent point with the firstimpression cylinder.

FIGS. 8-10 illustrate a sheet S2 of about one half the length of thesheet S1 illustrated in FIGS. 24 inclusive. A wrinkle W2 is alsoillustrated in sheet S2. The trailing edge of the sheet S2 is engaged bythe suction device 58 and while the leading edge of sheet S2 is engagedby gripper 32 on impression cylinder 12, the suction device 58 moves ina counterclockwise direction as illustrated in FlGS. 8-10 to exert atension on sheet S2 and remove the wrinkle W2. After the perfectinggrippers 72 and two-color grippers 74 havepassed beyond the tangentpoint between perfecting cylinder and impression cylinder 12, theperfecting grippers 72 rotate outwardly to position the perfectinggripper pad 90-beneath the trailing edge of the sheet S2. The sheet isthen engaged by the gripper fingers 92 of perfecting gripper assembly 72and the perfecting gripper assembly. 72 is tumbled inwardly asillustrated in H0. 9 where the trailing edge of the sheet is transferredfrom the perfecting gripper assembly 72 to the twocolor gripper assembly74 and is thereafter transferred from the perfecting cylinder 10 to thesecond impression cylinder 14 in the same manner as previouslydescribed.

Although dependent rotation of the perfecting gripper assembly 72 andtwo-color gripper assembly 74 is illustrated and described, it should beunderstood that the inward and outward tumbling of the perfecting andtwo-color gripper assemblies 72 and 74 may be practiced as isillustrated and described in the Gegcnheimer et'al. patent. With thelatter arrangement. however, it is essential that both the perfectinggripper assembly 72 and the two-color gripper assembly 74 pass beyondthe tangent point-of the adjacent cylinders 10 and 12 before the gripperassemblies 72 and 74 begin'to tumble outwardly so that there will'be nointerference between the two-color gripper assembly 74 and the surfaceof the first impression cylinder 12.

The suction exerted by the suction head 68 on the sheet should besufficient to engage the sheet and hold the sheet as it is transferredto the perfecting gripper assembly 72. Where, however, the sheet is notwrinkled as hasbeen illustrated and described, provisions are made topermit relative sliding movement between the sheet trailing edge and thesuction head. A stop member 67 associated with the suction device 58 sothat the trailing edge of the sheet is always in proper registry. Thesuction device 58 may be of conventional construction having aforaminous type suction head that engages the sheet when the vacuum hasa suction head that exerted thereon. The arm 64 is adapted forlimitedrotational movement about the axis of shaft 66 to move thesuction head along the periphery of perfecting cylinder 10. The extentof rotation of the suction device is relatively small to exert thedesired tension on the sheet before transfer to the perfecting cylinderfor proper registry.

It will be appreciated that while for purposes of illustration, specificgripper assemblies have been shown, other suitable gripper assemblieswill be apparent to those skilled in the art. The gripper assembliesmust be adapted to be retracted within the periphery of the perfectingcylinder when. passing the tangent point between the perfecting cylinderand the first impression cylinder.

According to the provision of the patent statutes, we have explained theprinciple, preferred construction and mode of operation of our inventionand have illustrated and described what we now consider to represent itsbest embodiments. However, we desire to have it understood that, withinthescope of the appended claims, the invention may be practicedotherwise than as specifically illustrated and described.

We claim:

1. A method of printing comprising:

printing upon a surface of a sheet on a first impression cylinder; I

engaging the trailing edge of said sheet while on said first impressioncylinder by a suction means on an adjacent transfer cylinder with theprinted surface of said sheet facing outwardly on said adjacent transfercylinder;

engaging the trailing edge of said sheet by first gripper means on saidtransfer cylinder while said sheet trailing edge is engaged by saidsuction means on said transfer cylinder;

transferring the trailing edgeof said sheet from said first grippermeans to second gripper means on said transfer cylinder; and thereaftertransferring the trailing edge of said sheet as the leading edge of saidsheet to an adjacent second impression cylinder from said second grippermeans and printing upon the opposite surface of said sheet on saidsecond impression cylinder. I

2. A method of printing as set forth in claim 1 which includes, movingsaid suction means in a direction opposite to the direction of rotationof said transfer cylinder to thereby exert a tension on said sheet bysaid suction means while said sheet is on said first impressioncylinder,

3. A method of printing as set forth in claim 1 which includes, engagingthe trailing edge of said sheet by said suction means at a locationadjacent the point of tangency between said adjacent first impressioncylinder and said transfer cylinder and moving said suction means in adirection opposite to the direction of rotation of said transfercylinder into abutting relation with a stop means.

4. A method of printing as set forth in claim 3 which includes, engagingthe trailing edge of said sheet by said first gripper means at alocation other than the point of tangency between said adjacent firstimpression cylinder and said transfer cylinder.

5. A method of printing as setforth in claim 1 which includes:

engaging the leading edge of said sheet by third gripper means on saidfirst impression cylinder;

engaging said sheet trailing edge by said suction means on said adjacenttransfer cylinder while said sheet leading edge is engaged by said thirdgripper means on said first impression cylinder; and

moving said suction means along the periphery of said transfer cylinderin a direction opposite the direction of rotation of said transfercylinder after said sheet trailing edge is engaged by said suction meansand said sheet leading edge is engaged by said third gripper means onsaid first impression cylinder to thereby exert a tension on said sheetwhile on said first impression cylinder.

6. A sheet fed offset printing press assembly comprising:

a perfecting cylinder positioned between a first and second impressioncylinder to sequentially receive and transfer the trailing edge of asheet from said first impression cylinder as the leading edge of saidsheet to said second impression cylinder, said perfecting cylinderhaving a saction device along the periphery thereof;

actuator means to actuate said suction device so that the sheet isengaged by said suction device while the sheet is secured on said firstadjacent impression cylinder andthe sheet is engaged by said suctiondevice after release thereof by said adjacent impression cylinder, saidactuator means arranged to actuate said suction device and engage thesheet at a location adjacent the trailing edge of the sheet;

said perfecting cylinder having first gripper means pivotally mountedwithin said perfecting cylinder and disposed closely adjacent to saidsuctionmeans, said first gripper means positioned to receive and engagethe trailing edge of the sheet prior to release of the sheet by saidsuction device on said perfecting cylinder and to secure the sheet tosaid perfecting cylinder after release of the sheet by said suctiondevice;

said perfecting cylinder having second gripper means pivotally mountedwithin said perfecting cylinderand disposed closely adjacent to saidfirst gripper means, said second gripper means positioned to receive thetrailing edge of the sheet from the first gripper means and engage thetrailing edge of the sheet prior to release of said trailing edge ofsaid sheet by said first gripper means and to secure said sheet to saidperfecting cylinder after release of the sheet by said first grippermeans; and

said second gripper means arranged to transfer the sheet to a secondadjacent impression cylinder as the leading edge of the sheet so thatthe trailing edge of the sheet is transformed into the leading edge ofthe sheet on the second impression cylinder.

7. A sheet fed offset printing press assembly as set forth in claim 6which includes propelling means to move said suction means along theperiphery of said perfecting cylinder and exert a tension on the sheetwhile the sheet is engaged on the first impression cylinder.

8. A sheet fed offset printing press'assembly as set forth in claim 7 inwhich said propelling means is timed to move said suction means alongthe periphery of said perfecting cylinder when said suction means is ata location adjacent the point of tangency between said first impressioncylinder and said perfecting cylinder.

9. A sheet fed offset printing press assembly as set forth in claim 6which includes means to pivot said first and second gripper means intimed relation to each other and tumble said first and second grippermeans inwardly toward each other within the periphery of the perfectingcylinder when said first and second gripper means pass through the pointof tangency between said first impression cylinder and said perfectingcylinder.

10. A sheet fed offset printing press assembly as set forth in claim 6in which said means to pivot said first gripper means is arranged totumble said first gripper means outwardly beyond the periphery of saidperfecting cylinder when said first gripper means is at a location otherthan the point of tangency between the perfecting cylinder and firstimpression cylinder to engage and transfer the trailing edge of thesheet from the suction means.

i 11. A sheet fed offset printing press assembly as set forth in claim10 in which said means to pivot said first gripper means is arranged totumble said first gripper means inwardly and transfer the trailing edgeof the sheet from said first gripper means to said second gripper means.

12. A sheet fed offset printing press assembly as set forth in claim 11in which said means to pivot said second gripper means is arranged totumble said second gripper means outwardly beyond the periphery of theperfecting cylinder to transfer the trailing edge of the sheet as theleading edge of the sheet to the second impression cylinder.

